Chemistry Conversion Modules

Normally pollutants are treated independently – one pollutant per particle. However multiple pollutants per particle can be defined by enabling the simple in-line-chemical conversion module through the Advanced / Configuration Setup / Concentration menu.  To demonstrate this capability first run the base simulation (right) for one pollutant, configured similar to the previous example (NAM 40 km, 6-h duration), but with a 100 m starting height.

Next configure the model for two pollutants, through the Pollutant, Concentration Grid, Deposition setup menu (below).  Give each pollutant a unique name and configure the 2^nd pollutant for no emissions.  Running the model with this configuration will give the about the same result as before. 

Enable the 10%/hour chemical conversion module through the Advanced / Configuration Setup / Concentration / In-line chemical CONVERSION MODULES menu. Rerunning the model will now produce concentrations from the second pollutant. Multiple pollutants can be selected from the Concentration Display menu.  The All option sums pollutants onto one map.

The default 10% per hour conversion is not very interesting.  The rate can be modified by creating a chemrate.txt file to define the species index and for this example a 50% conversion rate.  If the file is placed in the model startup directory, the conversion module will use these values and produce the following results for the two pollutants.